1. Field of the Invention
The present invention relates to a head suspension having a piezoelectric element that deforms in response to an applied voltage, an actuator having such a piezoelectric element, and a method of attaching such a piezoelectric element to an actuator attaching part.
2. Description of Related Art
A head suspension is a device installed in, for example, a hard disk drive to write and read data on a hard disk of the hard disk drive. Such a head suspension may have an actuator in which a piezoelectric element is attached to an actuator attaching part.
A head suspension, an actuator, and a method of attaching a piezoelectric element to an actuator attaching part according to a related art will be explained with reference to FIGS. 15A to 15F.
FIGS. 15A to 15F are sectional views, in which FIG. 15A illustrates an actuator attaching part 103 and a contact 111a of a flexure 111, FIG. 15B illustrates a condition that a first adhesive AD1 is applied to the actuator attaching part 103, FIG. 15C illustrates a condition that a piezoelectric element 113 is bonded to the actuator attaching part 103, FIG. 15D illustrates a condition that the first adhesive AD1 is solidified; FIG. 15E illustrates a condition that a second adhesive AD2 is filled between the piezoelectric element 113 and the actuator attaching part 103; and FIG. 15F illustrates a condition that the piezoelectric element 103 is fixed to the actuator attaching part 103 with the adhesives AD1 and AD2.
The piezoelectric element 113 is attached to the head suspension as illustrated in FIGS. 15A to 15F.
In FIG. 15A, the actuator plate 101 of the head suspension or the actuator has the actuator attaching part 103. The actuator attaching part 103 has an opening 105 and actuator supports 107 and 109 each having a recessed shape. In the opening 105, there is positioned the contact 111a of the flexure 111. Onto the contact 111a, conductive paste EP is applied.
In FIG. 15B, the first adhesive AD1 is applied to the actuator supports 107 and 109.
In FIG. 15C, the piezoelectric element 113 is set on the first adhesive AD1 so that the piezoelectric element 113 is bonded to the actuator supports 107 and 109 through the first adhesive AD1. At this time, an electrode surface of the piezoelectric element 113 is electrically connected through the conductive paste EP to the contact 111a of the flexure 111.
In FIG. 15D, the first adhesive AD1 solidifies.
In FIG. 15E, the second adhesive AD2 is filled between the actuator supports 107 and 109 and the piezoelectric element 113.
In FIG. 15F, the second adhesive AD2 solidifies and unites with the first adhesive AD1, thereby fixing the piezoelectric element 113 to the actuator attaching part 103.
The related art uses the first adhesive AD1 to correctly position the piezoelectric element 113 in the actuator attaching part 103 and the first and second adhesives AD1 and AD2 to surely fix the piezoelectric element 113 to the actuator attaching part 103.
In this way, the related art involves a plurality of steps to apply and harden the adhesives. Namely, the related art must apply the first adhesive AD1, harden the first adhesive AD1 after placing the piezoelectric element 113 thereon, fill the second adhesive AD2 between the actuator supports 107 and 109 and the piezoelectric element 113, and harden the second adhesive AD2. These adhesive applying and hardening steps are time-consuming to deteriorate productivity.
Further, the adhesives freely flow in the actuator attaching part 103 and frequently ooze due to the capillary action into unintended gaps between the piezoelectric element 113 and any one or more of actuator plate 101, flexure 111, and other parts of the head suspension. If this happens, the rigidity, spring load, and dynamic characteristics of the head suspension will be spoiled or varied.
This and other related arts are Japanese Unexamined Patent Application Publications No. 2002-050140, No. 2002-184140, and No. 2010-79944.